十三分之五×【一又五分之二+(6.5-二又三分之一÷一又三分之二)】
= 5/13×[7/5+（6.5-7/3÷5/3）]
=5/13×[7/5+(6.5-7/3×3/5）]
=5/13×[7/5+(6.5-7/5）]
=5/13×[7/5+6.5-7/5]
=5/13×6.5
=5/2